Sheet feeding device for printing machines



Dec. 24, 1957 w. P. KOCH 2,817,521

SHEET FEEDING DEVICE FOR PRINTING MACHINES Filed July 2, 1952 s Sheets-Sheet 1 Elm-Ill FWMAQ- Her/* Dec. 24, 1957 w. P. KOCH SHEET FEEDING DEVICE FOR PRINTING MACHINES Filed July 2, 1952 5 Sheets-Sheet 2 Inventor: WEf/Vd 29w roe/ Dec. 24, 1957 w. P. KOCH 2,3

SHEET FEEDING DEVICE FOR PRINTING MACHINES Filed July 2, 1952 3 Sheets-Sheet 3 2,817,521 Ce Patented Dec. 24', .1 957 SHEET FEEDING DEVICE FOR PRINTING MACHINES Werner Paul Koch, Offenbach (Main), Germany, assignor to Faber & Schleicher Aktiengesellschaft, Olfenbach (Main), Germany, a German body corporate Application July 2, 1952, Serial No. 296,838 A Claims priority, application Germany July 4, 1951 5 Claims. (Cl. 271-62) This invention relates to machines for working on sheets, such as printing machines, for example, and more especially to the devices which are used for feeding the sheets to be operated upon int-o the machine. It is usual in these machines to feed the sheets from a pile, and devices are known, in which the pile can be changed while the machine remains at work, and it is to this class of device that my invention bears particular reference. And it still more refers to that type of sheet feeding devices, in which a rigid bottom part is adapted to carry the full Weight of the pile, and a thin flexible top part to carry only a remainder portion of the depleted pile when the major portion has already been used up. The introduction of a new pile then takes place while the remainder portion of the pile still continues to feed the printing mechanism.

Although devices of the class referred to have been in use for feeding sheets into printin machines, for example, they were possessed of far reaching disadvantages, which either prevented their general use or which were too elaborate to be practical, or time consuming and diflicult to handle, and it is, therefore, the main object of the invention to eliminate the aforesaid disadvantages and to provide a sheet feeding device which will answer all practical requirements and be simple and strong of construction and easy of manipulation.

Another object of the invention is the provision of rockable supporting means at about the top of the feeding device for gripping and supporting the flexible table top while the bottom part of the table is withdrawn, and to continue the feed without the necessity of a separate elevator for the tip-movement of the remainder portion of the depleted pile.

With these and other objects in view the invention substantially consists in the provision of a sheet feeding device in which the bipartite pile table is transported in upward direction by only one set of chains in connection with means, on said chain, for grasping and carrying the said pile table, while other stationary means are provided for holding the top part of the table after the greatest part of the sheets has been used up, so that another complete pile table consisting of top and bottom and supporting another pile of sheets is conveyed upwardly by the same set of chains. And the invention preferably also consists in the provision of automatic and preferably electrically controlled means for returning the set of chains and the carrying means fixed thereto while the top part of the pile table is being held suspended.

In a preferred embodiment of the invention, the transportation mean-s may first begin to lift the thin table top, andafter an advance of only a few millimetres the lower part will also be raised, whereby the weight of the pile will bend or bulge the thin sheet of the table top so that it comes to rest on the more sturdy table bottom and be sustained thereon.

The higher the pile is raised and the more of the sheets are taken away from its top, the less will be the weight of the pile which, toward the end, decreases so that the thin table top reassumes its original flat position and thereby comes clear of the bottom part, which can then easily be removed. In this position of the remainder of the depleted pile a new main pile is wheeled into the device and placed in readiness for being lifted. The upper part, or table top, has meanwhile reached a position in which it is seized in accordance with the invention by a set of stationary holding pawls or the like, upon which the table top with its remaining small number of sheets comes to rest, so that the same set of conveyer chains is free to transport the new main pile up to the table top in the upper part of the feeding device.

For returning the chains to take up a new pile while the remainder of the depleted pile is being held suspended, the invention provides automatic, preferably electric controls, as for instance by providing one of the holding devices with an electric contact, by the closing of which an electro-magnet may be caused to engage or disengage the clutch for the power drive of the conveyer chains. The action of disengaging the clutch may, for instance, close a circuit for moving the conveyer chains downwardly. An abutment provided on the chain actuates in its lowermost position a contact, through whichthe set of chains is reversed and moved up again. Hereby the new pile is lifted by its carriers up to and into contact with the table top suspended in the holding means. The said holding means, thereby, are released and the contact which is carried by one of them, is opened. This sets the electric motor at rest whereas the mechanical transportation means are again put into operation.

The accompanying drawings diagrammatically illustrate two embodiments of the invention by way of example. In these drawings:

Fig. 1 illustrates one embodiment of the invention having a table top which is U-shaped at its sides; the arrangement being shown in front elevation.

Fig. 2 is a side elevation of the device shown in Fig. 1.

Fig. 3 shows a part of a device similar to that shown in Fig. 1 in which one of the holding means is provided with an electric contact, and with one of the carriers in its lowest position.

Fig. 4 is a similar view to that shown in Fig. 3 in the position of the parts after the main pile has taken over the transport of the rest pile.

Fig. 5 shows the position of the parts after the table top has been removed.

Fig. 6 represents an electric diagram for the control of the conveyer chains.

As seen in Figs. 1 and 2 the pile 1 rests upon the upper part, or top, of the pile table, which is denominated 2 and which is made of sheet metal and provided along its sides with U-shaped guide channels 3 and 4. These channels may be formed integral with the table top 2, 'or they maybe made separately and attached to the same subsequently. Into this U-shaped guide 3, 4 the table bottom 5 can be pushed in. This lower part is preferably formed of rigid board, strong enough to support the full weight of the pile. -A carriage 6 servesto wheel the pile 1 into the feeding device ready for transporting it upwardly by the carriers or grippers 7 which are provided on the chains 8. These chains move over sprockets 9, 10 which are journalled in the frame 11 of the feeding device.

When the pile has been used up to the height of the remainder of the depleted pile approximately indicated at 1a at the top of Fig. 1, its weight has become so light that it can be sustained by the thin metal plate 211 forming the table top, while formerly, under the full weight of the pile, the table top is deflected so as to rest with its greater part on the bottom part as shown in the lower part of Fig. 1. In the position 2a of the table top the bottom part a has become free and can be withdrawn. At about the same time the U-channels 3a, 4a are seized by the holding pawls 12 and held there until the next main pile has been moved up. This is rendered possible insofar as by the seizure of the pile 1a by the holding pawls 12 the chains 8 have become free and the next set of grippers 7 can be used to raise the new main pile 1 until it contacts with the remainder of the depleted pile, or with the table top respectively, from below. The main pile then takes over the further transport of the rest pile, and the table top 2a can also be extricated.

As is diagrammatically indicated in Figs. 3 to 5, one of the pawls 12 is provided with an electric contact 24 which will be closed, when the table top 2a is, in this instance, settled on the resting surfaces of the pawls so that current will flow through the electro-m-agnet 25 (Fig. 6) and thereby disengage the clutch (not shown in the drawing) for the power drive 9a of the chains indicated in dotted lines in Figs. 1 and 2. Fixed to the core 26 of the electro-rnagnet is a retainer 27, to which a cam 28 is pivoted. When the core of the electro-magnet is shifted by the magnet being energized, the cam 28 moves past the roller 29 of a lever 30. The lever is thereby lifted so as to close a contact 31 in the control circuit, upon which a safety switch 49 comes into action to initiate the return movement of the chains 8 by means of an electric motor which, to avoid crowding of the drawing, is not shown.

In order to permit the cam 28 to remain in position during the closing of contact 31, it is acted upon by a spring 32 which tends to pull the cam bodily against an abutment 33. When the chains 8 have been returned sufliciently far for the carriers 7 to have arrived in their lowermost position as shown in Fig. 3, a lever 35 becomes depressed by an abutment 34 on one of the chains, so as to cause its pin 36 to rock a bell crank lever 37 (Fig. 6). The vertical arm of this bell crank lever 37 supports the horizontal arm 38 of another bell crank lever. The rocking movement of lever 37 trips the lever 38 so that the latter is pivoted by a spring 39 about its axis 40. The lever 38 being thus turned, its arm 41 will close the contact 42, whereby the circuit through the down switch 49 is interrupted and the circuit through the up switch 51 closed. A hook 43 on one of the chains 8 then lifts the lever 38 into its elevated position, whereupon the spring 44 pulls the bell crank lever 37 to catch under the lever arm 38. A bolt 45 is provided to serve as a stop for lever 37.

In the operation of the device the carriers 7 lift the two parts 2 and 5 of the pile table, with the pile of sheets resting thereon, off the carriage 6 and transport them upwards until the table top in the position 2a begins to be lifted by the pile 1 ascending from underneath (Fig. 4). Hereby the table top 2a is lifted out of contact with the holding pawls 12 and thereby causes the contact 24 to open. This opening of the contact deenergizes the magnet 25, which, thereby, reengages the clutch for the power drive in upward direction.

At the same time with the backward movement of the magnet core 26, the cam 28, while contacting with the roller 29, is pressed against an abutment 46, because of the spring 47 being stronger than spring 32. This causes the contact 31 to be lifted only halfway in order to in- 4 terrupt the circuit which cuts out the motor, whereupon the table top 2a may be removed so that the remainder of the depleted pile and the new pile form a combined pile. Two button switches 48 and 50 in the control circuits are provided to initiate the up and down movement by hand if desired.

What I claim is:

1. In a sheet feeding device for use in printing machines having a pile table comprising a rigid bottom part and a flexible top part loosely supported thereon, chain means for raising both the said table parts with the main pile of sheets resting thereon into contact with the printing mechanism of the machine, and means for supporting the said flexible top part with a depleted portion of the pile when the major portion thereof has been used up, said supporting means comprising bearings at the upper end of the sheet feeding device, and table top supporting means rockably mounted in the said bearings for gripping and supporting said flexible table top part when the latter has been raised to a certain predetermined height, whereby the previously flexed table top part straightens and the bottom part thus comes free for withdrawal.

2. In a sheet feeding device for use in printing machines having a pile table comprising a rigid bottom part and a flexible top part loosely supported thereon, chain means for raising both the said table parts with the main pile of sheets resting thereon into contact with the printing mechanism of the machine, and means for supporting the said flexible top part with a depleted portion of the pile when the major portion thereof has been used up, said supporting means comprising bearings at the upper end of the feeding device, depending pawls pivotally mounted in the said bearings, and seating surfaces on the said pawls for supporting said flexible table top part when the latter has been raised to a certain predetermined height whereby the previously flexed-down table top straightens and the bottom part comes free for withdrawal.

3. In a sheet feeding device for use in printing machines having a pile table comprising a rigid bottom part and a flexible top part loosely supported thereon, chain means for raising both the said table parts with the main pile of sheets resting thereon into contact with the printing mechanism of the machine, and means for supporting the said flexible top part with a depleted portion of the pile when the major portion thereof has been used up, said supporting means comprising inwardly protruding brackets near the upper end of the feeding device, depending pawls pivotally mounted in the said brackets, seating surfaces on the said pawls for said flexible table top part when the latter has been raised to a certain predetermined height in the feeding device, means in connection with the said pawls for initiating the return movement of said chain means without alfecting the position of said flexible table top, and means operable at approximately the end of the return movement of said chain means to again reverse same in order to elevate a new pile of sheets previously brought in position on another pile table into contact of the table top part with the said pawls so as to rest on the seating surfaces thereof.

4. In a sheet feeding device for use in printing machines having a pile table comprising a rigid bottom part and a thin flexible top part loosely supported thereon, chain means for raising both the said table parts with a main pile of sheets resting thereon, and means for supporting said flexible top part with a depleted pile of the sheets resting thereon, depending lateral channels on the said flexible table top of a height greater than the thickness of the said table bottom for in and out-sliding said table bottom therein, said supporting means comprising pivoted pawls near the upper-end of the feeding device for gripping and supporting said flexible table top and allowing the rigid bottom part to be withdrawn from the said lateral channels, means in connection with at least one of the said pawls for reversing the travelling direction of the said .chain means, said reversing means being responsive to the weight of the table top resting on the said pawls, and other References Cited in the file of this patent means for again reversing the travelling direction of the said chain means so as to elevate a new pile of sheets into UNITED STATES PATENTS Contact With the flexible table top on said pivoted pawls 2,329,413 Neja Sept. 14, 1943 thereby permitting the withdrawal of the said table top 5 2,431,514 Seltzer Nov. 25, 1947 in order to unite the two piles of sheets. 2,549,364 Bobst Apr. 17, 1951 5. A sheet feeding device for printing machines as set 2,654,603 Williams Oct. 6, 1953 forth in claim 3, in which the said means for initiating the return movement of the chain are electrical contacts re- FOREIGN PATENTS sponsive to the weight of the table top when resting on the 10 595,921 Great Britain Dec. 23, 1947 seating surfaces of the said pawls. 595,922 Great Britain Dec. 23, 1947 

